Mainbeam jammer suppression using multipath returns

We propose a technique for the mitigation of mainbeam jammers that are spatially co-located with targets of interest. Spatial nulling methods are ineffective for these jammers since they cancel the target signal in their attempt to mitigate the interference. The traditional approach to this problem is to integrate very long pulses in order to boost the signal power and "burn-through" the mainbeam jammer. However, the long time periods necessary to acquire a single target in this manner occupy a large amount of the available radar resources and drastically reduce the number of targets the processor is able to track. We propose a method that makes use of terrain reflected jammer multipath energy to suppress the mainbeam jammer signal and significantly decreases the required integration time. Since the reflected signals are produced by the same source, i.e. the jammer, they are coherent with the direct-path signal. By exploiting this coherence, the proposed method is able to achieve partial jammer suppression, while maintaining the gain on the target, resulting in a reduction in burn-through time requirements.